1. Field of the Invention
The present invention generally relates to a depth-photographing method, and more specifically to a depth-photographing method of detecting human face or head by illuminating a target with a specific light, detecting the reflected light from the target with a detector, and generating depth information based on the detected result.
2. The Prior Arts
As the mobile communication or electronic devices become more popular, it is one of the primary goals for the manufacturers to improve the human-machine operation interface. Additionally, most of the devices generally operate with electric power supplied by the batteries, and thus it is crucial to effectively save power consumption during operation.
In the prior arts, power saving mode is usually used for specific operations to reduce most unnecessary power consumption. For example, when the electronic device is kept in the standby mode or idle state over a preset period of time, most power-consuming functions will be shut down, such as the display function, that is, the light source being turned off and the display operation being prohibited. Meanwhile, the user can make the device return to the normal operation mode from the power saving mode by use of some appropriate wakeup or recovery operation, so as to retrieve all normal functions temporarily prohibited, like image display. One of the most common used to recover is that the user needs to push a specific switch or press a specific key, and then a dialog box is popped up to prompt the user to follow the instructions, such as pressing the power key and then the confirmation key. Another example is the sliding unlock operation, which is applied to most of the touch screen devices. Specifically, the user is required to use his/her finger to press and drag an unlock icon/bar shown in the display unit.
One of the shortcomings in the prior arts is that the unlock operation procedure requires the users to press some specific keys in a preset order, and at the same time activate the power-consuming display function. As a result, the power consumption increases and the user has to focus on the instructions shown in the display device. Thus, the above-mentioned traditional unlock operation is complex and confusing, and particularly does not meet the requirement of the user-friendly interface.
Therefore, it needs a new depth-photographing method, which actively uses depth information to generate appearance information of the target, and determines if the target is a human face or head to generate depth photographing detection information for cancelling the lock state, thereby avoiding entering any unintentional power saving mode, speeding up entering the desired power saving mode, or changing/adjusting the display content to overcome the drawbacks in the prior arts.